RE: Microfluidics Chat Thread WAS: [DIYbio] Paper request

At the moment, my main strife is with my vacuum pump. Its a single stage that can kinda almost not really go to 29"Hg. The MIT nanomaker video on pdms oxidation via microwave oxygen plasma said we need to pull a vacuum of 6 torr or less (<29.8inHg) I don't really trust my vacuum gauge but after some fitting tightening and Teflon taping, I got it to go to 29"Hg. Most two stage pumps state they can down to 6 torr but I really don't feel like buying another pump albeit for the low price of $114.

I went to Brooklyn Glass a while back and the neon guy showed me air plasma in a neon tube but I forgot what pressure he pulled. The experiment here:

https://m.youtube.com/watch?v=fMUemBZ0k5Q

Is so simple but a few setbacks have made me a bit frustrated. The two all-plastic vales I installed into my Pyrex bottle cap had some fun quirks. That ended up causing a leak. I fixed that problem with some JB Weld but now it seems my vacuum pump can't pull low enough. I found a corona treater on eBay for cheap but only has the needle probe not the wide angle spreader. Worst case ill try that. Also found an interesting article on UV based pdms oxidation via ozone but its paywalled for me:

http://www.sciencedirect.com/science/article/pii/S0925400503007482

I'm getting the hang of draftsight but I don't trust the hatching it does to fill in the spaces to make a printable negative. It does a "low-poly" type fill that leaves these secant gaps around curves which may interfere with the channels. I guess I could just reflow the toner ink. I'm using shrinkydinks at the moment....

Why is it so complex to make simple shapes using CAD programs?!?! I actually found LibreCAD to be quicker to use. Seems like it has the same functionality and works fine for building fluidics. Just make sure to use closed polylines, not lines, and join them as you go. Kinda like compiling code often to avoid bugs later on.

In DraftSight, once u lay a polyline, just right click and hit arc to make curves. I always snap to grid and Ortho since my first circuits are just gradient generators and are more or less square with the grid. If the arc doesn't form in the direction you want, just right click and hit direction and draw a line in the direction you want and that should fix the arc issue. Once your chip circuit is done, highlight all the points and right click, editPolyline, type join, hit enter. That should make everything one big polygon if all is closed.

Sebastian S. Cocioba
CEO & Founder
New York Botanics, LLC
Plant Biotech R&D